Method and apparatus for pumping wells



March 17, 1959 J. B. MCGAY METHOD AND APPARATUS FOR PUMPING WELLS IN V EN TOR.

3 Sheets-Sheet 2 J. B. MCGAY METHOD AND APPARATUS FOR PUMPING WELLS March 17, 1959 Filed Feb INVENTvoA ATTORNEY March 17, 1959 J. B. McGAY METHOD AND APPARATUS FOR PUMPING WELLS Filed Feb. 12,v 1954 3 Sheets-Sheet 3 l a 0 0 n .FZ/g. H ATTO/Xyngm United States Patent O METHOD AND APPARATUS FOR PUMPING WELLS John B. McGay, Tulsa, Okla.

Application February 12, 1954, Serial No. 409,818

8 Claims. (Cl. 103-75) This invention relates to improvements in liquid pumps and more particularly, but not by way of limitation, to an improved liquid pump adapted for use in oil and water wells and the like.

As it is well known in the oil industry, the majority of producing oil wells are pumped by use of a rofl` type pump. The pumping unit is installed in the lower end of the oil well bore and is actuated by a string of rods from the surface. In some wells, and particularly those wherein the well bore deviates from the vertical, the rods will rub along the well tubing during operation of the ypumping unit and cause separation of the" rods. This, of course, results in a fishing operation to recover and reconnect the separated rods. s

The present invention contemplates a pumping apparatus for use in deep wells wherein a column of liquid is utilized as the connecting medium between the surface lower portion of the well and draw in a quantity of well y fluid. The invention utilizes the kinetic energy of the upwardly moving liquid column to bring in a supply of well liquid into the pumping apparatus. The liquid column is, in effect, bounced in a well tubing by the application of outside energy at the surface of the well 'and by using an elastic medium in the lower portion of y the well. Each time the column moves downwardly in the well tubing, a foot valve at the lower end of the tubing is closed to shut olf the lower end of the tubing from the well and provide a compression of the elastic medium. And each time the liquid column bounces'upwardly, the foot valve opens to admit a new supply of well fluid into the column.

i An important object of this invention is to pump la well without the use of a mechanical power transmitter extending through the major length of the well bore.

Another object of this invention is to provide a hydraulic type pumping apparatus for a well utilizing simply constructed moving elements in the lower portion of the well.

A further object of this invention is to provide a simply constructed liquid pump for use in wells which may be economically manufactured.

And another object of this invention is to provide a well pumping apparatus having a minimum of moving mechanical elements, and which may be economically operated.

An additional object of this invention is to provide a well pumping installation utilizing a minimum of moving parts in the lower portion of the well to reduce wear, corrosion and maintenance of the moving elements.

A still further object of this inventionis to provide a well pumping apparatus utilizing a bouncing liquid column `and elastic medium and having a quick closing -valve between the column and the elastic medium operable in accordance with the velocity of the liquidfcl- :2,877,712 Patented Mar. 17, 1959 umn. It is also an object to provide the maximum vacuum in such an apparatus during the upward movement of the liquid column and enhance the intake of well viiuid.

Other objects and advantages of the invention will be evident from the following detailed description, 'read in conjunction with the accompanying drawings, which illustrate my invention.

In the drawings:

Figure l is a vertical cross sectional view of my novel pumping apparatus installed in a well bore. i

Figure 2 is a View similar to Fig. 1 illustrating the downstroke of the pump.

Figure 3 is yanother view similar to Fig. l illustrating the upstroke of the pump. 1

Figure 4 is still another view similar to Fig. l illustrating the final phase of the upstroke of the pump.

Figure 5 is a vertical cross sectional view of a modiiied pumping apparatus installed in a well bore illustrating the downstroke of the apparatus.

Figure 6 is a view similar to Fig. 5 illustrating a later step in the operation of the modified pump.

Figure 7 is a vertical sectional view of another modifled form of the invention illustrating the downstroke of the apparatus.

Figure 8 is a View similar to Fig. 7 illustrating the beginning of the upstroke.`

Figure 9.is another view similar to Fig. 7 illustrating thefinal phase of the upstroke.

Figure 10 is a sectional view taken along lines 10-1 of Fig. 7.

Figure ll is a perspective view of an insert utilized in the pumping apparatus of Figs. 7 to 10.

' Referring to the drawings in detail, and particularly Fig. 1, reference character 2 designates the usual well casing extending downwardly in a well bore from the surface 3 to an oil reservoir 4. Ay well tubing 6 extends through the well casing 2 and is suspended therein Iby any suitable supporting means (not shown). j

The tubing 6 extends downwardly into the loil reservoir 4 and is externally threaded lat its lower end 8 for receiving an internally threaded seating member 10. They lower end 12 of the seating member 10 is tapered upwardly and inwardly to receive a circumferentialk projection or ange 14 provided on the upper face of'a hollow piston member 16. When the piston member 16 is in its upper position as shown in Fig. l, the valve projection 14 extends into the seating member 10 and is sealed thereto by a suitable sealing ring 18 carried around the projection 14.

The piston 16 contains a ball check valve 20 adapted to seat on a projection 22 in the lower end of the piston 16. A suitable spider-like retaining device 24 is secured in the upper inner portion of the piston 16 to limit'the upward movement of the' ball check valve 20. The piston reciprocates vertically in a cylindrical housing 26 below the well tubing 6. An apertured closure member 28 is threaded into the lower end of the housing 26 and provides an anchor for a helical spring' 30. The spring 30 extends upwardly through the housing 26 and is anchored at its upper end to the lower face of'the piston 16. The upper end 32 of the housing 26 is threadedly secured to another tubular housing 34 extending upwardly 'around the well tubing 6. The upper end 36 of the housing member 34 is lclosed off andsecured to the well tubing 6 for supporting the housing sections 26 and 34 in the vertical position shown in Fig. l. A suitable sealing ring 38 is disposed at the interconnection of the housing sections 26 and 34 to prevent an escape of uid downwardly around the piston 16 when thepiston is the position shown in Fig.-1. f

The well tubing 6 contains a liquid column 40 extend` ing from the upper end thereof downwardly into the piston 16. The ball check valve 20 normally closes off the lower end of the piston 16' and denotes the lower endof theliquid column 40. A gaseous iluidis con- Atainedin chamber 42 in the upperhousing -section 34 and exerts a pressure downwardly on the piston E16.

-Thewpressureof the gas inchamber 42 is substantially equal to the5pressure of the liquid column 40 `in the vicinity of` the piston'. The spring 30 is provided with a strength sufficient to hold the piston 16 slightly-below the seating member lil against the pressure of the column f40and gas in the chamber 42 when the liquid column is in a static condition. Therefore, when the liquid col- .umn y40 is moved downward, as will-be hereinafter set forth, the pressure exerted by the column 46 will be distributed over the entire cross sectional area of the piston 16 at the beginning of the downstroke.

A tubular housing 44 is secured on the upper end of the well tubing 6 above the surface 3 of the well. The housing 44 forms a small reservoir around the tubing 6 and has an outlet conduit 46 extending therefrom and communicating with a storage tank or'the like (not shown). A tubular member 48 extends upwardly from the housing 44 and reciprocally receives aplunger 50. The cylinder 43 is of a size corresponding to the tubing 6 whereby the plunger 50 may move downwardly into the upper end of the tubing 6, as will be hereinafter `set forth. A link 52 is pinned to the upper end of the plunger 50 and extends upwardly into pivotal connectionwith a prime mover shown schematically vand designated by reference character 54. The prime mover 54 may be of any suitable type to provide a reciprocation of the link 52 and plunger 50.

Uperaton Upon movement of the prime mover 54 in the direction of the arrow as shown in Figs. 1 and 2, the plunger 50 is moved downwardly through the cylinder 48 into the upper end of the well tubing 6. The plunger 50 .forces the liquid column 40 present in the well tubing downwardly against the piston 16 and ball check valve .20. Thus, the liquid column 40 acts as a fluid piston to retain the ball check valve 20 in a closed position as shown in Figs. 1 and 2 and moves the piston 16 and valve ange 14 downwardly in the housing section 26 against the action of the spring 30 as illustrated in Fig. 2. This provides communication between the tubing 6 ,and chamber 42 and a portion of the liquid from-the column 40 ows upwardly around the seating member 10 into the lower end` of the upper housing section 34 to compress the gaseous fluid present in chamber 42. The plunger 50 moves downwardly at a rate .of speed sufficient to provide a momentum that will continue the downward movement of the liquid .column 40after the plunger 50 has stopped. The liquid `column 40 will therefore be bounced against the piston l16 and gas in chamber 42 to enhance the returning speed of the liquid column as will be hereinafter set forth. The :plunger y50 preferably does not maintain a complete fluid'tightnt with the tubing 6, therefore, only a slightvacuum will becreated above the downwardly moving liquid column 40 and it will not materially retard the downward movement of the column 40.

As the downwardly moving liquid column 40loses its momentum, the compressed spring 30 (through'the medium of the piston 16) andthe compressed gas in chamber 42 force the liquid column40 back upthrough the tubing 6 .as shown in Fig. 3. lThecheck valve .20 remains closed during the upward movement of` the piston.16, and the compressed gas from chamber 42.forces the liquidcolumn from the housing section .A34 Tdownwardly around the seating member into the upwardly moving .column .40. The prime mover 54.movestl1e plunger 50 upwardly ahead of the upwardly.moving .tion for the column 40.

liquid column 40 to prevent a shock being imposed on the plunger 50 and to prevent a retarding of the upwardly moving liquid column 40. After the plunger 50 is moved above the tubing 6 as shown in Fig. 4, the upper end of the liquid column 40 reaches the housing 44 and a portion of the column fluid is discharged through the housing 44 and outlet conduitv46.

The combined effect of the gas in chamber 42 and upwardly moving piston 16 provides a 'relatively high velocity for the liquid column 4l). When the piston 16 seats on the Vseating member 10, the liquid column 40 has reached its maximum velocity, and the resulting kinetic energy continues to move the column in an upward direction. This continued upward movement creates a vacuum in the piston 16 and the lower end of the well tubing 6 to open the check valve 20 and draw in well liuid from the reservoir 4 through the lower end of the vhousing member 26. It is to be noted that the spring'30 `provides `a quick closing movement of the piston 16 into contact with the seating member 10 to enhance the vacuum created at the lower end of the upwardly moving column 4i).

The well uid drawn from the reservoir 4 into the lower end of the well tubing 6 becomes a part of the liquid column 40, and when the pressure is equalized above and below the check valve 20, the valve 20 is closed. When the kinetic energy of the upwardly moving column 40 is dissipated, the liquid column will tend to fall or bounce back downwardly through the well tub- ,ing 6. This downward movement of the column 40 is assisted by again moving the plunger 50 downwardly as shown in Fig. 2 and repeating the cycle of operation.

To obtain the best results, the liquid column 40 is `maintained in constant motion by timed application of theplunger 50 to provide a substantially rhythmic mo- A large number of varying factors affect the speed of travel of the column 40, therefore, the exact rhythm for forcing the liquid column 40 `downwardly cannot be precisely predicted for each proposed installation. However, the timing can be easily determined by forcing the column 40 downwardly at various speeds and noting the time required for the column to return to the upper end of the tubing 6.

As previously stated, the gas in chamber 42 is preferably maintained at a pressure substantially equal to the pressure of the liquid column 40 in the lower end of the well tubing 6. This pressure may be obtained in various ways, such as by running a charging tube from the housing section 34 to the surface of the well or by charging the housing section 34 prior to installation thereof in the well casing 2. Ordinarily the gas in chamber 42 will be retained therein during operation of the apparatus and a recharging will not be necessary. It will also be understood by those skilled in the art that the plunger50, link 52 and prime mover 54 may be replaced by a suitable hydraulic mechanism to provide pressure impulses on the upper end of the liquid column-40, however, the invention is not limited in any manner to the type of prime mover.

.Figures 5 and 6 illustrate a modiedpumping apparatus wherein reference character 56 indicates a bell shaped housing threadedly secured to the lower end 8 of the. tubing 6 in the oil reservoir 4. A hollow piston 58 is reciprocally disposed in the housing 56 and is adapted toseat upon a downwardly facing circumferential shoulder 60 formed in the upper portion of the housing 56. The'piston 58 is moved upwardly in the housing 56 by a helical spring 62 extending downwardly from thepiston 58 and anchored to an inwardly extending circumferential shoulder 64 at the lower end of the housing 56. Al cup shaped valve 66 is adapted to close off the inner bore 68 of the piston 58. The valve 66 has a downwardly projecting rod 70 extending through the bore 68 and yanchoredto the underface of thel piston 58 bya small helical spring 72. It will `be apparent that thespring 72 ltends to retain the valve 66 in a closed position over the' bore 68.

In operation of the appara .'us shown in Figs. 5 and 6, the plunger 50 is moved downwardly as shown in Fig. 5 to move the liquid column 40 in a downward direction into the housing 56. The liquid column 40 exerts a pressure on the upper face of the piston 58 to move the piston 58 downwardly in the housing 56 against the vaction of the spring 62. In addition, the liquid column 40 assists the spring 72 in retaining the valve 66 in a closed position. The plunger 50 operates in the same manner as previously described in connection with Figs. 1 to 4 to provide a substantial velocity for the liquid column 40 and bounce the column 40 against the spring 62.

At the end of the downward movement of the liquid column 40, the spring 62 forces the piston 58 in an upward direction to raise the column 40 at a relatively high velocity. As the piston 58 seats on the shoulder 60, the liquid column 40 reaches its maximum velocity and creates a vacuum in the upper portion of the housing 56 to open the valve 66 and draw in well liquid from the reservoir 4 through the housing 56 and piston 58 into the well tubing 6. Simultaneously, a portion of the liquid constituting the column 40 is discharged through the housing 44 and outlet conduit 46. When the kinetic energy of the column 40 is dissipated and the column 40 stops moving in an upward direction, the spring 72 closes the valve 66. Simultaneously, the plunger 50 is again moved in a downward direction as shown in Fig. to repeat the cycle of operation.

It will be observed that the spring 62 takes the place of the gas in chamber 42 and spring 30 of the embodiment shown in Figs. 1 to 4. The spring 62 is of a strength to retain the piston 58 slightly below the shoulder 60 when the liquid column 40 is in a static condition, and to provide the maximum pressure area for the liquid column 40 upon the initial downward movement of the column. The spring 62 will still provide a quick closing of the piston 58 on the shoulder 60 to enhance the vacuum created in the lower end of the well tubing 6.

Another modified form of the invention isr illustrated in Figs. 7 to l1 wherein reference character 74 (Figs. 7-9) designates a well tubing extending downwardly in a well bore (not shown) and having a bell shaped housing 76 rigidly secured thereto in any desired manner, such as by welding or the like. The housing 76 extends downwardly around the tubing 74 into the oil reservoir (not shown) and has another tubular housing 78 connected to the lower end thereof by means of a threaded coupling 80. The housing 78 extends downwardly from the housing 76 and in aligned relationship with the well tubing 74 for receiving and supporting an insert or cage member 82.

The cage insert 82 (Fig. 11) is substantially tubular in form with an outer periphery corresponding in size to the inner periphery of the housing 78. Four upwardly and inwardly inclined flat surfaces 84 are formed on the upper end of the insert 82 and are arranged generally in the shape of a pyramid. An aperture 86 is formed vertically in each of the surfaces 84 in communication with the interior of the insert 82 for the flow of fluid therethrough as will be hereinafter set forth. A lug or projection 88 extends upwardly from the outer edge of the insert 82 opposite each of the at surfaces 84 and is providedA with a groove 90 in the lower inner face thereof which forms a continuation of the respective surface 84. The surfaces 84 are generally triangular in outline and terminate at their upper ends in a threaded hub 92 of a size to threadedly engage the lower end 94 of the well tubing 74 as illustrated in Figs. 7 to 9.

An annular shaped bushing 96 is threadedly secured to the lower end of the cage 82 to support the lower end of a helical compression spring 98. The spring 98 extends upwardly inthe insert 82 to receive and support an annular plate 100. From Fig. 7 it will be apparent f6 I that the spring 98 constantly urges the plate 100 upwardly toward a downwardly facing circumferential seating shoulder 102 formed in the inner periphery of the insert 82. The inner diameter of the plate is equal to o'r larger than the diameter of the well tubing 74 and the inner periphery 103 and may be ilared upwardly if desired (not shown). Four circumferentially spaced arms 104y (see also Fig. 10) extend upwardly from the plate 100 through the respective apertures 86, and each has a valve plate 106 pivotally secured to the upper end thereof above the insert 82. Each valve plate 106 is of a size to engage the respective flat surface 84 of the insert 82 and close off the respective aperture 86 whenin a down or closed position as shown in Fig. 9. Also, the arms 104 are of a length to retain the lower ends of the valve plates 106 in proximity with the respective flat surfaces 84 when the plate 100 is in the upper or open position as illustrated in Figs. 7 and 8.

A bushing 108 is also threadedly secured in the lower end 110 of the housing 78 below the bushing 96. An aperture 112 is formed in the central portion of the bushing 108 to provide a passageway for the well fluid as will be hereinafter set forth. A cup shaped foot valve 114 is positioned above the bushing 108 and has a stem or rod 116 extending downwardly therefrom through the aperture 112. The valve 114 is of a size to close off the aperture 112 and prevent a downward llow of uid through the bushing 108. A circumferential shoulder 118 is formed on the lower end of the valve stem 116 to receive an upwardly extending helical compression spring 120. The spring 120 surrounds the valve stem 116 and is anchored at its upper end to a pair of arms` or bars 122 secured to the lower face of the bushing 108. Therefore, the spring 120 constantly urges the valve 114 downwardly into a closed position as illustrated in Figs. 7 and 8.

The well tubing 74 is iilled with a suitable liquid to form a liquid column 124 in the same manner as in the previously described embodiments. It will be apparent that the column liquid will also lill the communicating chambers of the insert 82, and the lower portion of the lower housing 78 above the foot valve 114. Furthermore, a gaseous uid in a chamber 126 is contained in the housing 76 provided above the insert member 82. The pressure of the gas in chamber 126 is substantially equal to the pressure of the liquid column 124 at the lower end 94 of the tubing 74, when the column 124 is in a static condition in order to position the interfacial level of the gas in chamber 126 and liquid column 124 at approximately the lower end 94 of the tubing 74. A sealing ring 128 is disposed in a circumferential groove 130 around the insert 82 to prevent a flow of fluids between the insert 82 and the housing 78. A suitable apparatus (not shown), such as the plunger 50, link 52 and prime mover 54 disclosed in Figs. 1 to 6, is provided at the upper end of the well tubing 74 to force the liquid column 124 downwardly and permit a discharge of liquid from the upper end (not shown) of the tubing 74 in a manner similar to that previously described.

In operation of the apparatus shown in Figs. 7 to 10, the liquid column 124 is bounced against the gas in chamber 126 in a rhythmic motion to provide a vacuum in the lower end of the housing 78 on each upstroke or upward movement of the liquid column 124 to draw in a supply of well iiuid through the aperture 112. Assuming that the apparatus is in a static condition, the foot valve 114 will be closed as shown in Figs. 7 and 8 and the liquid coiumn 124 will extend upwardly from the foot valve 114 through the housing 78, insert 82 and the well tubing 74 to the surface of the well. Also, the gas in chamber 126 is retained in the housing 76 under pressure in order to position the interfacial level of the gas, and the liquid comprising the column 124 in the vicinity of the lower end 94 of the well tubing 74.

When a force is applied to the liquid column 124 at 7 the surface of the well, the column will move downwardly and a portion of the columnliquid will ow from the lower end of the tubing 74 upwardly through the apertures 86, as shown by the arrows in Fig. 7, to compress the gas in chamber 126. During the movement of the column liquid from the tubing 74 into the housing 76, the spring 98 will retain the annular plate 100 in its upper position against the shoulder 102 and retain the valve plates 106 in their open positions. When the gas in chamber 126 is compressed sufficiently to overcome the momentum of the downwardly moving column 124, the gas will force the column liquid downwardly from the bell housing 76 through the apertures 86 and'back into the well tubing 74 as shown by the arrows in Fig. 8.

As the column liquid is discharged through the apertures 86 from the housing 76, it impinges upon the upper surface of the annular plate v100, and is directed upwardly toward the tubing 74 by the ared inner periphery 103 of the plate 100. It will be apparent that the column liquid impinging upon the plate 100 will provide a pressure differential across the plate 100 acting in a downward direction against the action of the helical spring 98. Furthermore, the force applied on the plate 100 will be controlled by the velocity of the column liquid. When 'the column liquid ilowing through the apertures 86 reaches a pre-determined velocity, the plate 100 will be moved downwardly a short distance to pivot the valve plates 106 inwardly to an inclined position (not shown) toward the surfaces 84. As the valve plates 106 are. pivotcd intol the path of movement of the column liquid, a pressure diierential willbe imposed thereon to quickly pivot the valve plates"106 further inward into engaging closed positions on the respective surfaces 84 over the apertures 86.

The momentum of the upwardly moving column liquid in the well tubing 74 will then draw the column'liquid from the insert 82 and housing 7S into the tubing 74 and create a vacuum in the lower end of the housing 78 above the foot valve 114. This vacuum raises the foot valve 114 against the action of the spring 120 as shown in Fig. 9, whereupon well liquid will be drawn through the aperture 112 into the housing 7S and become a part of the liquid c`olumn124. Simultaneously, a portion of the liquid comprising the column 124 will be discharged from the upper end of the well tubing 74 in the same manner as in the previously described embodiments.

When the momentum of the upwardly moving column 124 `is dissipated, the column 124 will tend to fallback downwardly through the well tubing 74. The vacuum in the lower end of the housing 78 will then cease to exist and the spring 120 will close the foot valve 114 to prevent a discharge of the column liquid downwardly through the aperture 112. Also, the spring 9S will return the plate 100 to its upper position against the shoulder 102, as shown in Figs. 7 and 8, to open the valves 106. When the liquid column 124 begins to fall through the well tubing 74, the surface apparatus applies a downward force to the column 124 to lrepeat the cycle of operation.

It will be observed that the valve plates 106 are closed in accordance with the velocity of the upwardly moving column 124. The tension of the spring 98 may be readily selected to provide a closing of the valve plates 106 at any desired velocity of the liquid column 124. Furthermore, the valve plates 106 are fast closing to provide a maximum vacuum in the housing 78 and enhance the intake of well fluid into the pumping apparatus.

From the foregoing, it is apparent that the present invention provides an apparatus for pumping wells wherein no mechanical power transmitting connection extends throughout the major portion of -the well. Thepower imposed by the prime mover is transmitted through a liquid column to compress an elastic medium arranged at the lower end of the well bore. The present inventionprovides a' hydraulic type pumping apparatus where-g in the moving elements disposed at the bottom of Va well bore are retained at a minimum. It will also be apparent thatthe apparatus may be economically'manufactured and operated.

"Changes may be made in the combination and arrangement of parts as heretofore set forth in the speci cation and shown in the drawings, it being understood that any modification in the precise embodiment of the invention may be made within the scope of the following claims without departing from the spirit of the invention.

I claim:

1. A well pumping apparatus comprising a well tubing extending downwardly in a well bore, a liquid column disposed in the tubing, means for applying energy to the upper end of the liquid column to cause a downward movement thereof, a housing disposed on 4the lower end oi' the tubing, a spring urged piston provided in the housing, said spring urged piston adapted to be moved downward simultaneous with the downward movement of the liquid column and provide communication be-y tween the tubing and the housing, and a gas provided in the-housing and adapted to be compressed by movement of the liquid column thereagainst, said gas adapted to cause reverse movement of the liquid column upon release of the applied energy therefrom, and valve means carried by the piston to alternately provide and close off communication between the tubing and the well fluid.

2. A well pumping apparatus comprising a well tubing extending downwardlyin a well bore, a liquid column disposed in the tubing, .cans for applying energy to the upper end of the liquid column to cause a downward movement thereof, a housing disposed on the lower end ofthe tubing, a spring urged piston provided in'the housing, said spring urged piston adapted to be moved downward simultaneous with the downward movement of the liquid column and provide communication between the tubing and the housing, a gas provided in the housing and adapted to be compressed by movementl of the liquid column thereagainst, said gas adapted to cause reverse movement of the liquid column upon release of the applied energy therefrom, and means carried' by the piston to alternately provide and close olf communication with the uid in the well bore, said means responsive to the reverse movement of the liquid column to provide communication between the tubing and the well lluid.

3. In a well pumping apparatus comprising an upstanding well tubing, a housing on the lower end of the tubing vhaving a gas chamber therein communicating with the tubing, a liquid column in the tubing, a prime mover at the upper end of the tubing arranged to intermittently force the liquid column downwardly through the tubing into the gas chamber, a compressible gas in the chamber adapted to react against the liquid column upon release or' the force of the prime mover and force the liquid column upwardly through the tubing, flow control means in the housing arranged to rapidly close communication between the gas chamber and the tubing during the upward movement of the liquid column in the tubing, and valve means carried by the flow control means to provide communication between the tubing and the well fluid during upward movement of the liquid column in order to lpermit'ow of well liquid into the tubing.

4. -A well pumping apparatus comprising a well tubing of a size to extend downwardly in the well, a liquid column disposed in the tubing, means for applying pre`s sure to the upper end of the liquid column and alternately releasing said pressure, a housing on the lower end ofthe tubing having a pressure chamber thereinA communicating with the tubing to receive the liquid column when pressure is applied thereto, said pressure chamber containing a gas adapted to be compressed by the application of pressure to the column, said gas causing `return of the liquid column to the tubing when pressure is released from said liquid column, said housing having an inlet ltherein communicating with the well fluid, a reciprocal piston in the housing having one end exposed to the uid inlet, said piston responsive to movement of the column to alternately provide and preclude communication between the pressure chamber and the tubing, and a valved passageway in the piston arranged to close off the fluid inlet from the tubing when the liquid column moves downwardly and provide communication between the tubing and the uid inlet when the liquid column moves upwardly.

5. A well pumping apparatus comprising a well tub ing extending downwardly in the well, a liquid column disposed in the tubing, means to alternately apply and release pressure to the upper end of the liquid column, a housing surrounding the lower end of the tubing and having a pressure chamber communicating with the tubing, said pressure chamber provided with a gas adapted to be compressed by the liquid column upon application cf pressure and to return the liquid column to the tubing when pressure is released from the liquid column, said housing having an inlet therein communicating with the well fluid, a reciprocal piston in the housing, a central bore in the piston, a valve provided in the bore of the piston, said valve responsive to movement of the liquid column downwardly to close oi the well uid inlet and responsive to reciprocal movement of the column to provide communication between the tubing and the Huid inlet, and spring means constantly urging the piston in a direction for obstructing communication between the pressure chamber and the tubing, said spring assisting in returning the liquid column to the tubing.

6. A well pumping apparatus, comprising a tubing extending downwardly in a well, a tubular housing surrounding the lower end of the tubing and closed at its upper end, a gaseous medium disposed in the housing, a hollow piston reciprocally disposed in the housing and arranged to close oi the gaseous medium from the tubing in one position thereof, valve means in the piston preventing ow of fluid downwardly through the piston, a spring in the housing continually urging the piston upwardly, a liquid column in the tubing, and means for intermittently forcing the liquid column downwardly to lower the piston and compress the gaseous medium in a rhythmic motion, said compressed gas causing reverse flow of the column upwardly between the intermittent force application.

7. A well pumping apparatus, comprising a well tubing extending downwardly in a well, a liquid column in the tubing, a housing on the lower end of the tubing having a pressure chamber therein communicating with the tubing, gas disposed in the housing, means for intermittently forcing the liquid column downward into the pressure chamber to provide a bouncing action of the liquid column against the gas, spring urged dilerential pressure sensitive ow control means in the housing arranged to close communication between the pressure chamber and the tubing when the liquid column is moved upwardly and provide communication between the pressure chamber and the tubing when the liquid column is moved downwardly, said housing having a iluid inlet therein. and a second flow control means in the housing arranged to close communication between the uid inlet and the tubing when force is applied to the liquid column and to provide communication between the liuid inlet and the tubing subsequent to the closing of the rst mentioned flow control means whereby a vacuum will be created in the housing adjacent the fluid inlet.

8. In a method of pumping an oil well which consists of imposing a downward force to a confined column of liquid in the well for moving said liquid column downwardly in a rhythmic motion, directing the downwardly moving liquid against an elastic medium, discharging the liquid into contact with a confined body of gas to provide compression of the gas while simultaneously precluding communication of the downwardly moving column of liquid with the liquid in the well bore, releasing said downward force against said column of liquid whereby said compressed gas imparts a reverse upward movement to the column of liquid, utilizing the kinetic energy of the upwardly moving column of liquid to create .a vacuum simultaneously with the upward movement of the liquid and provide communication with the well liquid for causing an upward flow of the well liquid, discharging a portion of the column of liquid at the surface of the well during the reverse upward movement thereof.

References Cited in the tile of this patent UNITED STATES PATENTS 1,114,108 Chance Oct. 20, 1914 2,379,539 Mercier July 3, 1945 2,486,617 Soberg Nov. 1, 1949 FOREIGN PATENTS 424,899 Great Britain Mar. 4, 1935 600,260 France Feb. 3, 1926 

